Temperature control means for sugar mingler



Mam}! 1956 c. A. OLCOTT 2,739,087

TEMPERATURE CONTROL MEANS FOR SUGAzR MINGLER I Filed D60. 10, 195] 2 Sheets-Sheet l INVEIIVITOR. (muff/l. 0L corr A TTOENE) March 20, 1956 c, QLCOTT 2,739,087

TEMPERATURE CONTROL MEANS FOR SUGAR MINGLER Filed Dec. 10 1951 2 Sheets-Sheet 2 E MW 1 so 3/ l MEAN! CONTROL MEAN! HEATER 529.4 a 4 PUMP damr4045 24 INVENTOR.

l 3: VALVE CHARM] 4. OLCOTT BY we #74 44 ATTORNEY United States Patent 2 395081 GONTRQE MEAtlNSrF-ORi SUGAR NIINGLER.

Charles A. Olcott, West Milford} N. J.

ApplicationDecember 10,; 1951-, Serial-No. 260592 6 Claims. (Cl. 127

This invention relates to sugar manufacturing and more" specifically to improvements" in a paratus for the heating or the-'massecui'te prior to itsprocessing" in a: bat= teryofcentrififgals;

ft is an objector the present invention to make more uniform the temperature of mixtures applied to thet'various centrifugals in a battery of such machines.

In the sugar refining art, it is the practice to heat the nrassecuite prior to its application to the centrifugal machines tde'n'su're' the proper temperature for the best results. Frequently the massec'uit'e' is"heated* by a long rotati'ngficoff fir-a: mixer tank overlying a battery of'centrifugals, say ten or" twelve, for example. With su h along coil, the problem arises of maintaining approxi rnately uniform heating in the mixture s'oth'atnrassecuite or" suhstantially the sametem eratureis applied to each: centrifugal" in the battery; Some su'ch installations i'n-' v'olvi ng a long mixer have operated a substantial differ'e'nce in temperature between the massecuite at one endand that at the other because thecirctrlf'ating'water in the mixer coil cannotive up heat"to-thernixtureirr the tank without becoming cooler and the'ternperat'ure thus becomes progressively lower along the length' of the coil. I

Various means have been tried in the past in an: at" tempt solve this problem but they have not been on tirely satisfactory. One attempted solutiontothe prob lem: hasbeen to feed the hot water into the: rotating coil fronrb'oth. ends and to fake-01f the cooled water from the middle but: it has been found that a. rotary joint with water on one side and massecnite on: the other is'very unsatisfactory.- Another way suggested to solvetheprohlem is to force the heating" water s0 fast: through the mixer that only a small drop in: temperature results. This theory,- however, lacks perfection: in practice for two reasons. First, it has been found that the viscosity of molasses doubles with every 9 degree drop in tempera ture so that' even a relatively small decrease in temperature-may 4 /2 degreesresults in an. increase of approximately 50% in molasses viscosity. This means that, ona given operating cycle, the dry charge of su'garat the cool: end contains 50% more molasses" than. the dry charge-at the hot end and this difference is very' detrimental in the process. Second, it isoften. not possi'hle to increase the flow of circulating. water because it is. not practicable-to increase the size of the pipesor to change the pump to'increase the water velocity.

Stillanother way of solving this problem is' to regulate the respective purging times. of the centrifugals in the group so that each operates on a cycle which will properly purge the massecuite. In other words; the centrifugal receiving a warmer mixture requires a smaller purging; period than one receiving a cooler mixture. However, there is a decided advantage in operating all of the centritugals in the group in the same cycle of op eration'.

In accordance with the presentinvention, a relatively even distribution of temperature is maintained in the ICC mixing; tank' and all". out-lets; therefrom receive heated material atthe same temperature by causing the heating water to flow'irr one direction through the rotatingboil for a predetermined interval of time and.then reversing the-water flowffor a like interval ofifti'ine'.v The correct time intervals can'h'e determined either by timing controls or by thermostatic" means. With the. present invention, all centrifngals in the group receive mas'secuite at the same-temperature soiallstart andendi their purging cycles at the same times.

In aspeeifiic exemplaryemhodiment of the. invention, a 4- way" valve is employed betweenrthe water pump and the two ends of a coil sectfom. In one position of the valve, the water entersoneiendof the coil section and flows out of the opposite end of" the section whileiiu the second'position" of the valve the water enters the latter end of' the coil sectforrand leaves'the former and. Thermostatic orti'tn'ermeansaie provided to operate the valve periodically d'nring the process from one ost t'i'on tothe other.

Theinvent ion will bemore readily understood; by referring to thefollowing description taken in connection with tfie" accompanying drawingsiforining a part thereof, in which: U I

Pig. 1 is a schematieelevation view, partly in cross section, of a multr-unft centrifugal installation. in accordance witlrthe invention-ihclbding apparatus for; heating the sugar bearing: material hefore its" application tothe con? tritugals and having oneform of" temperature responsive valve control means;

Fig. is" a schematic view ofaporti on of the appara; the of Fig. 1 showing the 4 way'valvepositionfor one direction of liquid flow through the: coil and including another form of temperature'responsive valve control means? v Fig.- 31 is a schematic view of the apparams of Fig. Z sliowi-hg-the positionoftheW-way'valve' for the opposite direction of liquid flow; and

Fig. 4 isa partial schematic view of time responsive valve control apparatus forthe 4-way, valve.

For a detailed descrt'ption-of 'the invention, a more specific reference is now madeto the drawings. Fig. I' shows; by way of example for purposes of illustratron-.21 mnl ti-unit sugar'centrifu'gal installation 10 embodying" a material heating arrangement in accordance withthe invention; The installation 10" includes a battery of centrifugals 11- of" any-suitable type used forthingsngar bearingmateria-l's. By-wayof example,'twelve centrifugals" have been shown'but obviously more or less than this number can be used; Overlying the centrifugals is a mixing tank 12- containing ahollow rotary coil 13 containing terminals 14 and I5 through which heating fluid (usually hot water} is admitted and removed firom the coili Any suitable coil can be used; satisfactory examples being-described in- Patent 2,055;- 778,-issued September 29', 1936, to G. E. Stevens and in Patent 2,178,805, issued November 7, 1939", to (Eharles A. Olcott'. The coil is rotated by anysuitable'means (not shown). Suitable outlets or conduits 16 connect the tank 12 with the centrifugals II; Above the mixing tank 12 is a battery ofcrystallizers 17 in which the sugar grains are crystallized from the syrup obtained from the low grade sugar-bearing mother liquors by boiling'in: vacuum pans; as is: welt known in the sugar refining. art.

The heating water is circulated through a sealed. loop into. which more water can. be added as desired. The water iscaused to be: forced through the loop by pumpv 18' which. is in a series pathincluding a heater 19, a first path through. the'4-way valvev 20, the coil. 13, and a secondv path through the. 4-way valve. .Referencewill now'be made to Figs. 2v and 3' in addition.to,Fig..1.

Fig. 2 shows a first position of the 4-way valve by means 3. of which the heating water enters the coil 13 at its left hand terminal and leaves it at the right terminal 15 while Fig. 3 shows the second position of the valve whereby the heating water enters the light terminal 15 and leaves through the left one 14. Arrows have been used in the drawing to indicate the directions of flow for the two valve positions.

In the practice of the present invention, the heating water is circulated through the coil from left to right for a predetermined period of time (for example, about one minute). The valve element'in the 4-way valve is then rotated 90 degrees from the first position (Fig. 2) to the second position (Fig. 3) and the water is passed through the coil in the opposite direction (that is, from right to left) for a second predetermined period of time, which preferably is the same as the first period of time but which may be made different if desired. By this means, the temperature of the material at each outlet 16 is the same as at all others. The valve 20 may be turned by hand but preferably automatic means are used to control the valve position. By way of example, three systems of automatic valve control have been shown in the drawings. The first two of these, shown in Figs. 1 and 2, respectively, are based on temperature changes while the third (Fig. 4) is time responsive.

The temperature responsive means of Fig. 1 comprises a thermocouple 21 positioned at one end of the mixing tank 12. When the, temperature of the massecuite 22 reaches a predetermined value, the member 21 causes a circuit including source of potential 23 and the coil of solenoid 24 to close, thus actuating the solenoid armature to change the position of the valve. When the temthe other so more heat would be desired at the left end than at the other. Under these conditions, there might be minutes of flow in the direction of Fig. 3 to compensate for the greatly cooling effect of incoming magma at the left hand end as compared with the right hand end.

Obviously, various changes can be made in the embodiments disclosed without departing from the spirit or letter of the invention. By way of example, pneumatic means can be used instead of solenoids for controlling the 4 way valve.

What is claimed is:

1. In combination, an elongated mixing tank for the temperature conditioning of sugar massecuite and the like, a relatively long, hollow, rotary stirring means or coil adapted to be rotated in said tank, a plurality of outlets for said tank spaced along the length thereof, means for applying temperature condtioning liquid to said coil and for removing it therefrom, and means for maintaining the temperature of the massecuite at each of said outlets substantially the same as that at all other outlets, said last-mentioned means comprising valve means for periodically reversing the direction of said liquid flow through said coil during the temperature conditioning process.

2. In combination, an elongated mixing tank for the temperature conditioning of sugar massecuite and the like, a relatively long, hollow, rotary stirring means or perature reaches a second predetermined value the electrical circuit is opened and the valve 20 is operated to its original position. sumed that satisfactory mixing can be accomplished if the mixer coil heating fluid averages 160 degrees F. If the water is heated to 165 degrees F. in the heater 19, the temperature at the input end is approximately this value and is at a much lower figure, say 155 degrees, at the exit end, thus averaging 160 degrees at the center of the coil.

A second temperature responsive means is shown in Figs. 2 and 3. This arrangement includes two elements 30 and 31 placed in the massecuite at respectively opposite ends of the mixing tank 12 and temperature-differential responsive control means 32 for energizing the solenoid 24 to actuate the valve 20 (the valve actuating means being represented schematically by the dash-dot connection 33) when the temperature of the element 30 at the left hand end exceeds the temperature of the element 31 by a predetermined amount, say 1 or 2 degrees. Controls responsive to temperature dilferentials are well known and available commercially so their detailed description herein is unnecessary.

Fig. 4 shows schematically a time-responsive means for controlling the valve 20 to periodically change the direction of flow in order to maintain a constant average temperature in the mixer. This embodiment includes a rotary timer 40 having contacts at appropriate places to energize and deenergize periodically one or more times each rotation the solenoid 24 to atcuate the valve 20. Many suitable timers are available commercially. By way of example, let it be assumed that the mixer holds about 4 charges for each centrifugal and that each charge takes about 10 minutes to dry. For this example, there would be a change of. massecuite about every 40 minutes. Very satisfactory results can be obtained if the flow of heating water is reversed every 20 minutes by the timer. However, it is desirable to have this reversal adjustable both as to frequency and to the length of time that the water flows in one direction as compared to the other. An example of when unequal time periods are desirable occurs when the inflow of cold massecuite is more pronounced at one end (say, the left) of the mixer than By way of example, let it be ascoil adapted to be rotated in said tank, a plurality of outlets for said tank spaced along the length thereof, means for applying temperature conditioning liquid to said coil and for removing it therefrom, and means for maintaining the temperature of the massecuite at each of said out lets substantially the same as that at all other outlets, said last-mentioned means comprising valve means for pcriodically reversing the direction of said liquid flow through said coil during the temperature conditioning 7 process and means responsive to the temperature of the massecuite for controlling the flow-direction reversal times.

3. In combination, an elongated mixing tank for the temperature conditioning of sugar massecuite and the like, a relatively long, hollow, rotary stirring means or coil adapted to be rotated in said tank, a plurality of outlets for said tank spaced along the length thereof, means for applying temperature conditioning liquid to said coil and for removing it therefrom, and means for maintaining the temperature of the massecuite at each of said outlets substantially the same as that at all other outlets, said last-mentioned means comprising valve means for pcriodically reversing the direction of said liquid flow through said coil during the temperature conditioning process and a timing mechanism for controlling the flowdirection reversal times.

4. In combination, an elongated mixing tank for the temperature conditioning of sugar massecuite and the like, a relatively long, hollow, rotary stirring means or coil adapted to be rotated in said tank, a plurality of outlets for said tank spaced along the length thereof, means for applying temperature conditioning liquid to said coil and for removing it therefrom, and means for maintaining the temperature of the massecuite at each of said outlets substantially the same as that at all other outlets, said last-mentioned means comprising valve means for periodically reversing the direction of said liquid flow through said coil during the temperature conditioning process, said flow reversing means including a 4-way valve.

5. In combination, an elongated mixing tank for the temperature conditioning of sugar massecuite and the like, a relatively long, hollow, rotary stirring means or coil adapted to be rotated in said tank, a plurality of outlets for said tank spaced along the length thereof, means for applying temperature conditioning liquid to said coil and for removing it therefrom, and means for liquid flow through said coil during the temperature conditioning process and means responsive to the difierence in temperature between the two ends of the mixing tank for controlling the flow-direction reversal times.

6. In combination, an elongated mixing tank for the temperature conditioning of sugar massecuite and the like, a relatively long, hollow, rotary stirring means or coil adapted to be rotated in said tank, a plurality of outlets for said tank spaced along the length thereof, means for applying temperature conditioning liquid to said coil and for removing it therefrom, and means for maintaining the temperature of the massecuite at each of said outlets substantially the same as that at all other outlets, said last-mentioned means comprising valve means for periodically reversing the direction of said liquid flow through said coil during the temperature conditioning process and means responsive to the change in temperature at one end of the mixing tank for controlling the flow-direction reversal times.

References Cited in the file of this patent UNITED STATES PATENTS France Aug. 11, 1921 

5. IN COMBINATION, AN ELONGATED MIXING TANK FOR THE TEMPERATURE CONDITIONING OF SUGAR MASSECUITE AND THE LIKE, A RELATIVELY LONG, HOLLOW, ROTARY STIRRING MEANS OR COIL ADAPTED TO BE ROTATED IN SAID TANK, A PLURALITY OF OUTLETS FOR SAID TANK SPACED ALONG THE LENGTH THEREOF, MEANS FOR APPLYING TEMPERATURE CONDITIONING LIQUID TO SAID COIL AND FOR REMOVING IT THEREFROM, AND MEANS FOR MAINTAINING THE THE TEMPERAUTURE OF THE MASSECUITE AT EACH OF SAID OUTLETS SUBSTANTIALLY THE SAME AS THAT AT ALL OTHER OUTLETS, SAID LAST-MENTIONED MEANS COMPRISING VALVE MEANS FOR PERIODICALLY REVERSING THE DIRECTION OF SAID LIQUID FLOW THROUGH SAID COIL DURING THE TEMPERATURE CONDITIONING PROCESS AND MEANS RESPONSIVE TO THE DIFFERENCE IN TEMPERATURE BETWEEN THE TWO ENDS OF THE MIXING TANK FOR CONTROLLING THE FLOW-DIRECTION REVERSAL TIMES. 